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The first cloned pigs are surprisingly healthy. The animals, born on 4 March,
have none of the problems that led to the deaths of many other clones in their
first few months. Alan Colman of PPL Therapeutics near Edinburgh, the company
that helped clone Dolly, says this could be because the pigs were cloned in a
two-step process. After fusing an adult pig cell with an egg whose genetic
material had been removed, as they鈥檇 done with Dolly, they removed the nucleus
and transferred it to a fertilised egg minus its own nucleus. Colman, who will
describe the results in a future issue of Nature, says this
double-nuclear transfer may somehow make the animals healthier.